A leading cause of disability and death in both the U.S. and abroad includes damage to a portion of the vascular system. This is a particular problem with regard to aortic aneurysms. Diseases of the aorta, for example, are becoming an increasing concern as a result of advancements in cardiac surgery and human longevity. Severe arterial sclerosis, severely calcified aorta, and other indications continue to necessitate complete or partial aortic replacement procedures.
Aneurysms are typically characterized by diseased or damaged blood vessels which lead to a weakening of the vessel wall. Weakening of the vessel wall can then lead to a blood-filled dilation of the vessel. Left untreated, aneurysms will eventually rupture and result in acute (and often fatal) hemorrhaging in a very short period of time.
The aorta has numerous arterial branches. The arch of the thoracic aorta, for example, has three major branches arising from the convex upper surface of the arch and ascending through the superior thoracic aperture to the root of the neck. The proximity of an aneurysm to a branch artery may limit the use of an excluding device, such as a tubular stent graft. For example, the main body or ends of a tubular stent graft may occlude or block the branch arteries as a result of positioning the stent graft against a healthy, i.e., non-diseased or dilated portion of the artery wall. Additionally, there may be an inadequate length of healthy tissue for the stent graft to seal against in the area between the aneurysm and the location of the branch arteries. Even if the stent graft is initially located without blocking a branch artery, there still is a risk that the devices will migrate to a position where it may partially or fully block a branch artery.